Nouns

(n)substantiveany word or group of words functioning as a noun

Adjectives

(a)substantive, essentialdefining rights and duties as opposed to giving the rules by which rights and duties are established“substantive law”
(s)substantial, substantiveof or relating to the real nature or essential elements of something“a substantial argument”
(s)meaty, substantivebeing on topic and prompting thought“a meaty discussion”